lOS 
Drought of 1870 and 
base, distributes more rapidly, and, under equal circumstances 
as to rain, is more liable to be washed into the subsoil or the 
drains, than is the ammonia of the ammonia-salts. Hence it is 
not applied until the commencement of active growth, when the 
plant is able rapidly to avail itself of it. It is also known that a 
portion of the ammonia of the ammonia-salts itself becomes con- 
verted into nitric acid, and then is subject, in like manner, to loss 
by drainage ; but to what degree a saturated condition of the 
soil during winter may cause serious loss, in this way, of 
the ammonia applied as ammonia-salts in the autumn, is a ques- 
tion not yet sufficiently investigated, and to which we shall 
make some further reference before concluding. 
Although, as has been said, there is no evidence at command 
in regard to wheat, in reference to the questions above raised, so 
direct as that referring to the meadow land, yet the results now 
to be adduced nevertheless supply interesting and important data 
in respect to the variation in the amount of moisture within the 
soil at different depths, as affected by season, by manure, and 
by the growth of the crop. 
Such were the drought and heat of May, June, and July, 
18G8, that it is hardly possible to suppose conditions more calcu- 
lated to induce extreme dryness of soil than those preceding the 
harvest of that year. Accordingly, towards the end of July, just 
before the crop was ripe, samples of soil were taken from three 
plots of the experimental wheat-field, with the special view of 
determining the amount of moisture retained at different depths. 
The plots selected were : — 
Plot 3. Without manure since 1839. 
Plot 2. With 14 tons farmyard manure per acre per annum. 
Plot 8a. With mixed mineral manure, and 600 lbs. ammonia- 
salts per acre per annum. 
The mode of collecting the samples was that already described, 
excepting that the iron frames employed were only 3 inches 
deep, instead of 9 ; the object being to determine the amounts 
of moisture at each 3 inches of depth, down to a total depth of 
36 inches, or rather below the pipe-drains. 
The subsoil of the farm consists of a tolerably tenacious 
reddish-yellow clay, resting upon chalk, and the corn crops 
seldom suffer from a scarcity of rain. At the time the samples 
were taken, the wheat had suffered but little from the drought, as 
the results already quoted show. But barley and oats were 
exceedingly light crops, and a bean crop in an adjoining field 
was quite dried up and dead for want of moisture. 
For comparison with these samples taken at a time of 
extreme dryness, others Avere collected from the same plots in 
January, 1869, after much rain during the preceding ten days; 
